I've done the trolleys twice now and it's quite boring. At least wiyh regular service you're always walking around. During our group meeting before Saturday morning preaching, the elder assigned some people to the trolley. One more person was needed but no one really wanted to volunteer to do the cart.
Under my experience, there have been some people who have gone up to the carts but it's only one or two at most. Sometimes no one comes up. My mother got a number of people but only because she went up to talk to them, although the rules are you aren't suppose to talk to anyone and just stand there. One time, to entertain myself and a kid that was with me, we played "I spy".